The Chinese patent publication CN1858438 disclosed a kind of vertical shaft wind power system, which does not have a shaft in the pivot of the fan blade. The fan blade turning round the shaft forms a wind wheel. And the range of the rotational angle of the fan blade is controlled by the automatic control system. Hence, the blade will achieve the best blade rotational angle in different positions.
However, no matter which way is adopted to change the rotational angle of the blade, there will still be the following defects:
When the rotational blades are in the surface following the wind, the angle between the wind and the rotational blades can not be 90°. Thus the fan blades can not face the wind in the best position. And when the fan blades are in the surface against the wind, the angle between the wind and the fan blades cannot be 0°. Hence, the wind power cannot be utilized sufficiently.
The Chinese patent publication CN101260865 disclosed a kind of an automatically adjusted angle fan blades, which makes the rotation shaft of the blade and the drive shaft related through the transmission of the meshing gears or chains. Then the fan blades will always be in the best position.
Nevertheless, there is a defect that the drive shaft and the blades are transmitted through meshing gears or chain directly, so that it will make the load too heavy when the fan blades are turning. Therefore the wind energy can not be utilized sufficiently, and that is also not conducive to the commercial development of the products.
The Chinese patent publication CN101260865 applies the hydraulic device to adjust the angle of fan blade, such as: hydraulic pump, hydrocylinder, hydraulic control valve and hydraulic accumulator and other accessories, in order to control the horizontal and vertical extension of the fan blade, thus to turn the fan blades to the best windward surface and to make full use of the wind power.
But the existing defect is that as the device adopts hydraulic equipment, such as: hydraulic pump, hydro cylinder, hydraulic control valve and hydraulic accumulator and other accessories, to control the stretch of the fan blade. The system control devices are added. Therefore the power consumption of the devices themselves greatly reduces the efficiency of the power generation.